/*
 * SLD Editor - The Open Source Java SLD Editor
 *
 * Copyright (C) 2016, SCISYS UK Limited
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.sldeditor.common.localisation;

import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

import com.sldeditor.common.console.ConsoleManager;

/**
 * The Class Localisation, the central point for getting localised strings.
 * <p>
 * The localisation is implemented as resource bundles.  The root folder is
 * <code>src/main/resources/i18n</code>
 * <p>Underneath is a folder for each of the top level folders in the source tree
 * containing all the package's classes.
 * <p>Calls are made to <code>getString()</code> supplying a class name.  The string is
 * looked up in the correspondingly named resource bundle.
 * 
 * @author Robert Ward (SCISYS)
 */
public class Localisation {

    private static final String DEFAULT_BASE_NAME = "sldeditor";

    private static final String COMMON_PREFIX = "common.";

    private static final String RESOURCE_FOLDER = "i18n";

    /** The Constant DEFAULT_COUNTRY. */
    private static final String DEFAULT_COUNTRY = "UK";

    /** The Constant DEFAULT_LANGUAGE. */
    private static final String DEFAULT_LANGUAGE = "en";

    /** The Constant ARG_STRING. */
    private static final String ARG_STRING = "-locale=";

    /** The instance. */
    private static Localisation instance = null;

    /** The current locale. */
    private Locale currentLocale = null;

    /** The resource bundle map. */
    private Map<String, ResourceBundle> resourceBundleMap = new HashMap<String, ResourceBundle>();

    /**
     * Instantiates a new localisation.
     */
    private Localisation()
    {

    }

    /**
     * Gets the single instance of Localisation.
     *
     * @return single instance of Localisation
     */
    public static Localisation getInstance()
    {
        if(instance == null)
        {
            instance = new Localisation();
        }

        return instance;
    }

    /**
     * Parses the command line.
     *
     * @param args the args
     */
    public void parseCommandLine(String[] args)
    {
        String language = DEFAULT_LANGUAGE;
        String country = DEFAULT_COUNTRY;

        if(args != null)
        {
            for(String arg : args)
            {
                if(arg.startsWith(ARG_STRING))
                {
                    String locale = arg.substring(ARG_STRING.length());

                    String[] components = locale.split("\\:");

                    if(components.length == 2)
                    {
                        language = components[0];
                        country = components[1];
                    }
                }
            }
        }

        currentLocale = new Locale(language, country);
    }

    /**
     * Gets the resource bundle.
     *
     * @param baseName the base name
     * @return the resource bundle
     */
    public ResourceBundle getResourceBundle(String baseName)
    {
        ResourceBundle resourceBundle = resourceBundleMap.get(baseName);

        if(resourceBundle == null)
        {
            if(currentLocale == null)
            {
                currentLocale = new Locale(DEFAULT_LANGUAGE, DEFAULT_COUNTRY);
            }

            try
            {
                resourceBundle = ResourceBundle.getBundle(baseName, currentLocale);
                resourceBundleMap.put(baseName, resourceBundle);
            }
            catch(MissingResourceException e)
            {
                ConsoleManager.getInstance().error(this, "Missing resource : " + baseName);
            }
        }
        return resourceBundle;
    }

    /**
     * Gets the string for the supplied class and key.
     *
     * @param clazz the class to get the strings for
     * @param key the key
     * @return the string
     */
    public static String getString(Class<?> clazz, String key) {

        String baseName = null;
        String className;

        if((key != null) && key.startsWith(COMMON_PREFIX))
        {
            baseName = DEFAULT_BASE_NAME;
            className = "SLDEditor";
        }
        else
        {
            String fullPackageName = clazz.getPackage().getName();
            String[] packages = fullPackageName.split("\\.");

            if(packages.length == 2)
            {
                baseName = DEFAULT_BASE_NAME;
            }
            else
            {
                baseName = packages[2];
            }

            className = clazz.getSimpleName();
        }

        ResourceBundle resourceBundle = getInstance().getResourceBundle(String.format("%s/%s/%s", RESOURCE_FOLDER, baseName, className));

        if((resourceBundle == null) || (key == null))
        {
            return key;
        }
        else
        {
            if(resourceBundle.containsKey(key))
            {
                return resourceBundle.getString(key);
            }
            else
            {
                return key;
            }
        }
    }

    /**
     * Gets the field.
     *
     * @param clazz the class to get the strings for
     * @param key the key
     * @return the field
     */
    public static String getField(Class<?> clazz, String key) {
        return getString(clazz, key) + " :";
    }

    /**
     * Preload a resource bundle.
     *
     * @param clazz the class to preload
     */
    public static void preload(Class<?> clazz) {
        getString(clazz, null);
    }
}
